Nickel manganese steel alloy and method of treating the same



Patented Jan. 1, 1929.

UNITED STATES PATENT OFFICE.

CHARLES MCKNIGHT, J'B., OF MONTCLAIR, AND THOMAS H. WICKENDEN, OF ROSELLE, NEW JERSEY, AND YAUL D. MEBICA, OF NEW YORK, N. Y., ASSIGNORS TO THE IN- TERNATIONAL NIGKEL COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY.

NICKEL-MANGANESE STEEL ALLOY. AND METHOD OF TREATING THE SAME.

No Drawing.

Our invention relates to alloy steels and particularly to those containing nickel, manganese and carbon, in the proportions of carbon .10 to .60% (preferably .35 to .5070) 5 manganese .70 to 2% (preferably .90 to 1.10%) and nickel .50 to 3.50% (preferably 1.50 to 2%). The other vmetalloids may be in ordinary proportions, and we prefer that the steel shall contain silicon from .10- to 50% (preferably .15 to 25%) with the sulphur and phosphorus each under 05%. Any other elements will be merely incidental.

We have discovered that if such a steel is subjected to a mild heat treatment, as for 5 example, an annealing, a double annealing,

or quenching in air and drawing, the material is particularly desirable for forgings, particularly heavy forgings. It is also desirable for structural shapes and plates,

I-bars, oil fieldJdrilling-tools and railroad rails.

'In carrying out our invention, we may make, the alloy steel in any desirable way, as for example, by the open hearth (acid or basic), electricfurnace, crucible, or Bessemer method. Such a steel is particularly adapted to mild heat treatment, as distinguished from the drastic heat treatment of heating and quenching in liquids. We dis- 50 pense with this drastic treatment, whereby the steel is heated to above the critical point and quenched inliquid, and impart to such a steel adesirable set of physical properties by a mild heat treatment, such for example,

as follows:

a. Simply heat the steel to a tempe permit it to cool slowly either in the furnace or in some insulating material, such as lime or ashes;

b. A double anneal which maybe carried so heating the steel to or over thecritical point,

holding it. at such temperature sufiiciently v rature above the critical point (about 1400 F.) and.

Application filed January 26, 1925. Serial No. 4,957.

long to thoroughlysoak the steel and accomlish the heat transformation, and then alowing it to cool in quiescent 'air. It is then again heated to a predetermined temperature, preferably about 1200 F., allowed to renqam at this point for a suitable time to insure thorough soaking, and then again cooled, either in a quiescent air or in a furnace.

Such a treatment will, if properly carried out, give the steel the following desirable tensile properties: j

Yield point or elastic limit about 55,000 to 80,000 psi. 1

Ultimate tensile strength, 85,000 to 110,000

Elongation, 20 to 30%.

Reduction of area, 40 to These properties may, of course, be varied 1 somewhat by varying the heat treatment which, however, should preferably always be of the mild type.

This steel, thus heat treated, is particularly desirable in the field of heavy forgings for railroad and similar work. Also for automobile parts, structural shapes and plates, oil field drilling tools, railroad rails, etc.

This treatment does not require quenching tanks and handling equipment, and hence, it is particularly adapted for shops not e material is preferably treated in its secondary or worked condition, as distinguished from the primary or cast condition.

Other alloying elements or metalloids may be added, the details of the gentle or mild heat treatment may be varied, and other variations may be" made without departing from our invention. I

While our alloy'steel is particularly adapted for a mild heat treatment and has the herein described desirable cha acteristics imparted to it by such treatmen it is also a 511-- perior alloy adapted for other forms of heat treatment, including the more drastic ty e.

By the words in alloying proportions we mean manganese in such proportions in the final alloy that the manganese has 'a discernible and material effect on the properties of the, material in coaction with the other elements of the alloy, as distinguished from a case where manganese is added for deoxidizing purposes and there remains in the metal v merely a small negligible content of managanese, which content has no material coactive effect with the other parts of the alloy as regards the properties thereof. I

We claim:

1. An alloy steel containing nickel 0.5% to v 3.5%, carbon 0.1% to 0.6%, and manganese in alloying proportions from about 0.9% 'to 2.0%, said alloy being capable'of developing in heavy sections high physical properties and ductility by mild heattreatment.

2. As a new article .of manufacture, anair:

being capable of developing high physical properties ment.

4. As a new article of manufacture, an aircooled forging of heavy section containing and ductility by mild heat treat- 1.0% to 2.5% nickel, 0.1% to 0.5% carbon, and manganese in alloying proportions from I about 0.9% to 2.0%, said art cle having enhanced physical properties with good ductil-' ity obtained by mild heat treatment.

5. As a new article of manufacture, an ar ,t-icle of over 1 inch in cross section containing 0.5% to 3.5% nickel, 0.1% 'to 0.6% carbon, and manganese in alloying proportions from about 0.9% to 2.0%, and which after niild heat treatment comprising air quenching and drawing will show properties of p 55,000 to 80,000 psi'yield point and 80,000 to 110,000 psi tensile strength.

6. Asa new article of manufacture, an alloy steel containing nickel 0.5% to 3.5%, carbon 0.1% to 0.6%, manganese in alloying proportions from about 0.9% to 2.0%, and having throughout high physical properties imparted by mild and gentle heat treatment.

7. As a-new article of manufacture, an article of over 1 inch in cross section containing-1.0%to 2.5% nickel, 0.1% to 0.5% carbon, and manganese in alloying proportions fromabout 0.9% to 2.0%, and which after .mild heat treatment comprising air quenching and drawing will show properties of 55,000 to 80,000 psi yield point and 80,000 to 110,000 psi tensile strength.

In testimony whereof we have hereunto set Q our hands.

CHARLES MGKNIGHT, JR. I THOMAS H. WICKENDEN.-

MERICA. 

